Modification of legs in insects
Structure of typical insect legs Consist of 5 segments namely Coxa , trochanter, femur , tibia and tarsus . Tarsus consist of 1-5 small segments called tarsomeres. Last tarsomere bears a pair of claws A pad between the claws is called Arolium Pads at the base of claws are called pulvilli
While the legs are normally adapted for walking many insects have them modified for variety of functions. Various modifications are Saltatorial legs –Hind legs adapted for leaping of jumping . The femur is greatly enlarged giving articulation for large muscles of tibia which are used in jumping occur in Grasshopper , Cricket
Raptorial :- Forelegs are modified for grasping the prey Occur in praying mantis
Scansorial The legs of louse are modified for clinging the tibia being stout and bearing at one end a thumb like process with a distal tarsal segment and a curved pretarsal claw . While grasping the body , tarsus and pretarsus work against the thumb
Natatorial The hind legs are adapted for swimming. Femur, tibia and Ist foretarsal segment are broad and flat with dense flat setae serving as oars Occur in aquatic beetles
Foragial Legs of honeybee are adapted for various functions . There is a pollen comb on inner surface of Ist segment of hind tarsus to remove pollen from body, A pollen basket on outer surface of hind tibia Spur on the apex of middle tibia to scrape pollen from the baskets Antennal comb on the front legs to remove pollen from antennia
Cursorial Legs are long and slender for running occur in cockroach
Fossorial Stout , spade like legs for digging in ground Occur in mole cricket
Stridulatory Legs have sound producing apparatus Occur in cricket Auditory Legs with sound producing tympanum Occur in long horned grasshopper